Mineralpedia Details for Simpsonite
Simpsonite
Named for Dr. Edward Sydney Simpson, a mineralogist and mineral analyst for the Western Australian government. An uncommon mineral, Simpsonite can be found in Australia, Brazil, Zimbabwe, the Democratic Republic of the Congo, Russia, and Canada as an accessory mineral in tantalum-bearing granite pegmatite. Simpsonite has a bluish-white cathodoluminescence and fluorescence under short wave ultraviolet light and can, rarely, fluoresce yellow.
Ref. Handbook of Mineralogy, Anthony et al (1995) and MSA at http://www.handbookofmineralogy.org/pdfs/simpsonite.pdf
- Formula
- Al4Ta3O13(OH)
- Crystal System
- Trigonal
- Crystal Habit
- Euhedral Crystals, Prismatic, Striated
- Cleavage
- None, None, None
- Luster
- Vitreous - Adamantine
- Color
- brownish yellow, colorless, white, light brown, light yellow
- Streak
- white
- Class
- Trigonal - Pyramidal
- Fracture
- Brittle - Conchoidal
- Hardness
- 7-7.5
- WebMineral
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- Mindat
- View Simpsonite
Simpsonite from Alto do Giz pegmatite, Rio Grande do Norte, Brazil
1cm partial crystal showing several faces.
A superb crystal of Simpsonite showing three good crystal faces one with striations. In association are small bladed, cherry red to orange, Tantalite-(Mn) crystals and altered zone of glassy green Hydrokenomicrolite.
Simpsonite from Tabba Tabba peg., Wallareenya Station, Western Australia, Australia
- Special Info
- Type Locality
There are no less than six, white to pinkish white, hexagonal crystals from 4 to 6mm of Simpsonite on this specimen. It is essentially all Simpsonite and this is the type locality.
Simpsonite from Tanco pegmatite, Bernic Lake, Manitoba, Canada
- Special Info
- Illustrated in London's book "Pegmatites"
Banded Aplite composed of reddish grains of Microlite, Albite and Simpsonite. The Simpsonite glows bright blue under SW FL. Illustrated on page 74, Fig. 4-18g.
